The answer to 'heat exchanger not cooling' is that the heat exchanger in your HVAC system may not be working properly, preventing it from cooling your home effectively. This can be caused by a few common issues, such as a clogged or dirty heat exchanger, a malfunctioning blower fan, or a refrigerant leak.
If the heat exchanger is clogged with dirt, dust, or debris, it can't properly transfer heat, leading to poor cooling performance. The blower fan is responsible for circulating air over the heat exchanger, and if it's not working correctly, the airflow will be restricted. Additionally, a refrigerant leak will reduce the system's ability to absorb and transfer heat, resulting in insufficient cooling.